Life Cycle Assessment Of Copper And Tungsten Tailings Recycling Process

In this paper,using the method of life cycle assessment,taking copper,tungsten tailings and their resource utilization process as the research object,taking on-the-spot investigation combined with relevant information,the input and output flow of raw materials,energy and so on in the process of resource utilization were studied qualitatively and quantitatively,and the data list was obtained.The eFootprint online analysis software was used to study the environmental impact assessment.This paper mainly studies the environmental impact in the process of copper tailings storage,copper tailings preparation of foam ceramics,tungsten tailings reconcentrate and recovery of tungsten concentrate and tungsten tailings reconcentrate and recovery of tungsten concentrate residual tailings as raw materials to prepare autoclaved aerated concrete.The original process of tungsten tailings reconcentrates and recovery of tungsten concentrate is compared and optimized,and the production of autoclaved aerated concrete prepared by secondary tailings is compared with that of traditional autoclaved aerated concrete.By quantifying the material,energy consumption and pollutant emissions of each stage in the process of tailings recycling,the most serious stage of environmental impact and environmental impact indicators are analyzed and determined,and the stages and treatment methods that need to be optimized is clarified.(1)The life cycle assessment model of copper and tungsten tailings storage was constructed.The dry method was used to store 1 t of tailings,and the impact on the environment was mainly the normal/normal discharge of CO2 and wastewater that were less consumed after the tailings pond occupied the land,and the discharge of overflow water.Based on eFootprint online analysis software,the environmental impact model of storage was established,and the life cycle assessment(LCA)results of the environmental impact on copper and tungsten tailings storage are calculated.The final LCA results show that copper and tungsten tailings have a great impact on the environment,so the resource utilization of copper and tungsten tailings is a very good way to reduce the impact of tailings storage.(2)A life cycle model for the production of 1 m3 copper tailings foam ceramics was constructed.The production process mainly involves grinding and mixing unit process,sintering and cutting unit process and embryo and drying unit process.In the production process of copper tailings foam ceramics,the largest contribution rate was the grinding and mixing unit process,and the main three environmental impact values are Global Warming Potential(GWP),Water Use(WU)and Primary Energy Decrement(PED).The life cycle model of 1 m3 copper tailings foam ceramics was constructed.The production process mainly involves grinding and mixing unit process,sintering and cutting unit process,and embryo and drying unit process.In the production process of copper tailings foam ceramics,grinding and mixing unit process have the greatest environmental impact,mainly Global Warming Potential(GWP),Water Use(WU)and Primary Energy Dissipation(PED).In the grinding and mixing unit process,the contribution to cement in PED and GWP is the highest,and the contribution to tap water in WU is the highest.In order to reduce the environmental impact in the production process of copper tailings foam ceramics,more green materials can be used to reduce the environmental impact caused by the consumption of raw materials such as cement,and the process and equipment can be upgraded to reduce the environmental impact caused by the consumption of tap water.(3)The life cycle model of recovery of 1 kg tungsten concentrate by total flotation process and gravity-flotation combined process was constructed and the effects of the two processes on the environment were compared.The results show that the gravity separation-flotation combined process compared with the total flotation process,not only the use of flotation reagents is reduced,the cost is reduced,and the environmental pollution is reduced.Therefore,compared with the total flotation process,the gravity separation-flotation combined process is preferred to recover 1 kg tungsten concentrate.On the premise of ensuring product quality,exploring more efficient and environmentally friendly flotation reagents can better reduce the environmental impact of tungsten concentrate recovery process.(4)The life cycle assessment model of 1 m3 autoclaved aerated concrete produced by traditional autoclaved aerated concrete method and secondary tailings autoclaved aerated concrete method is constructed and the influence of the production process of the two methods on the environment is compared.The results show that the secondary tungsten tailings have less environmental impact on the production of autoclaved aerated concrete,and reduce the consumption of sand,cement and other materials.Therefore,compared with the traditional autoclaved aerated concrete production,the secondary tungsten tailings autoclaved aerated concrete method is preferred.Under the premise of ensuring product quality,in order to achieve the purpose of clean production,energy conservation and emission reduction,the use of green materials instead of raw materials can better reduce the impact of autoclaved aerated concrete production process on the environment.